1. Field of the Invention
The present invention relates to an optical pickup to be used in a disk device such as a DVD recorder and a DVD player, and more particularly relates to an improvement in a structure of the optical pickup for attaching, to a dumping gel box, a connection wiring and elastic wires which extend from a lens holder.
2. Description of the Prior Art
A United State patent application publication No. 2005/0195702 discloses an optical pickup having elastic wires extending from a lens holder and partially extending through gel material for attenuation of vibration of the elastic wires.
The inventor of the present invention built a prototype of an optical pickup having more practical structure as shown in FIG. 5. The prototype optical pickup includes an actuator 3 mounted on a metal sliding base 2 which is supported by guide rails 1 to reciprocate in a radial direction (as shown by arrow a-b) of a disk D (see FIG. 1(b)). The optical pickup comprises a metal actuator base 4 for fixedly mounting the actuator 3 at a predetermined position on the sliding base 2, a dumping gel box 6 of synthetic resin material fixed on the actuator base 4 by a screw 5, a lens holder 7 including an objective lens OL and arranged on the actuator base 4 to oppose the dumping gel box 6, a permanent magnet 9 fixed to a supporting plate 4a which in turn is cut from the actuator base 4 and bent upward, with the permanent magnet 9 being located close to a plurality of coils 8 (a focusing coil, a tracking coil and tilting coil) mounted on the lens holder 7, and a yoke 4b which is cut from the actuator base 4 and bent upward and extends upwardly within the lens holder 7.
Grooves 11 are formed at approximately central positions on both sides 6a of the dumping gel box 6 such that the grooves are open at the top and bottom of the dumping gel box 6. The prototype optical pickup configured as mentioned above may be assembled by a following process. A connection wiring 13 of a flexible printed circuit formed with a plurality of lands 12 on both ends thereof, is folded in substantially U shape and is brought into close contact with a back surface 6b and the both side surfaces 6a of the dumping gel box 6, with the lower side of the connection wiring 13 extending along the upper surface of the actuator base 4, such that side openings of the grooves 11 are closed by the end portions 13a of the connection wiring 13. Then, the grooves 11 are filled with thermosetting adhesive 14 which, in turn, is heated, for example, at 80° C. for 20 to 30 minutes to be set and adhere the both end portions 13a of the connection wiring 13 to the respective side surfaces 6a of the dumping gel box 6. Next, a plurality of elastic wires (three wires for each side in the illustrated prototype) soldered at P to the lens holder 7 at their one ends 15a, are soldered to respective lands 12 of the connection wiring 13 at their other ends 15b to form soldering portions P. The connection wiring 13 is electrically connected to a control circuit board 16 mounted on the sliding base 2. The dumping gel box 6 is filled with dumping gel material G through which the elastic wires 15 extend.
As for the process for reading information from the disk, a control section including a microcomputer built in the disk device performs control operation to supply electric current from the control circuit board 16 through the connection wiring 13 and the elastic wires 15 to respective coils 8 to drive the lens holder 7 by the interaction of the electromagnetic field caused by the coils and the permanent magnet 9 mounted on the actuator base 4, with laser beam being projected on the disk D through the objective lens OL and reflected beam being detected to read the information recorded on the disk D.
According to the configuration of the prototype optical pickup as mentioned above, the side openings of grooves 11 are closed by the end portions 13a of the connection wiring 13 and the bottom openings of respective grooves 11 are also closed by the actuator base 4 while only the top openings of the grooves 11 are open. Accordingly, when the thermosetting adhesive 14 is filled in the grooves 11 through the top openings, air in the grooves 11 can not escape from the grooves 11 and accumulates in the lower portions of the grooves 11 so that the thermosetting adhesive 14 can not be filled in the grooves sufficiently due to the accumulation of the air and the end portions 13a of the connection wiring 13 are likely to peel from the side surfaces 6a of the dumping gel box 6 at the portions concerning with the accumulated air. When the peeling of the connection wiring 13 occurs, the connection between the elastic wires 15 and the dumping gel box 6 becomes uncertain and it will be difficult to accurately drive the lens holder 7 as desired.